The combined therapy of ADT and SRT to the Prostate bed for recurrence after surgery is becoming more mainstream in clinical practice.
This is because of the synergy when combining the two. There is also the issue of systematic vs focal disease. You may have systematic (micro metastatic) disease outside the proposed area of radiation that is too small to be seen on imaging such as the C11 Choline at Mayo so the ADT deals with that.
One thing to ask your medical team about is whether to include pelvic lymph nodes in the radiation treatment and if so, how high in the pelvic lymph nodes do they radiate? Mayo has data on that.